Colt Anaconda

Glock 17

Shotguns

Mossberg 500

In the Pilot episode, "The Long Road", a shorty Mossberg 500 shotgun was used by one of the bandits at the market. It had a cut-down barrel and magazine tube, forward and rear pistol grips, heat shield, and extra shell holder. This is the exact same shotgun that was previously used in Reindeer Games, 3000 Miles to Graceland, Smokin' Aces 2: Assassins' Ball, and a whole bunch of other movies and TV shows filmed in Vancouver.

Mossberg 500 Cruiser with heat shield & foregrip - 12 gauge

From Episode 1x01, "The Long Road"

From Episode 1x01, "The Long Road"

From Episode 1x01, "The Long Road"

Submachine Guns

Ruger MP9

A Ruger MP9 is carried by a member of Kurdy's (Malcolm-Jamal Warner) former gang in (Season 2, Episode 11) "The Past Is Prologue".

Ruger MP9 with stock extended - 9mm

Assault Rifles

M16A2

The M16A2 was one of the most commonly-seen weapons on the show; nearly all of the various militia factions and bandit gangs seen throughout the show used them in bulk. However, all M16A2s seen on the show were Tokyo Marui airsoft replicas. No real M16A2s were ever used; whenever M16s were fired, they were always Olympic Arms K4Bs (Colt Model 715 clones) and early slab-side M16s.

From Episode 1x04, "And the Ground, Sown with Salt" (this one is a rubber cast of an M16)

XM177/GAU-5 mock-ups

In Episode 1x05, "To Sail Beyond the Stars", Valhalla Sector assassins were seen using XM177/GAU-5-type carbines, which were mocked-up from other AR-15 carbine variants and fitted with fake XM177-style compensators. Curiously, one of them had what appears to have been a Rocky Mountain Arms Patriot Pistol upper receiver (it was a flattop with no forward assist or brass deflector, which means it couldn't have been made by Colt).

Olympic Arms K3B + Cobray CM203

In Episode 1x08, "Firewall", Markus (Peter Stebbings) grabbed an unusual-looking AR carbine fitted with a Cobray CM203 37mm launcher (standing in for the M203) when he planned to kill Major Quantrell (Michael Rooker). This is an 11.5" Olympic Arms K3B-FT carbine fitted with a mock XM177-type flash hider; it is recognizable by its older-style flat top receiver (with a 2nd Gen OlyArms proprietary rail, prior to the introduction of Picatinny).

Late Model Cobray CM203, not attached to a rifle - 37mm flare

From Episode 1x08, "Firewall"

From Episode 1x08, "Firewall"

L1A1

Seen in Cory's Armory in (Season 2, Episode 4) "Deus Ex Machina"

L1A1 with wood furniture and 20 round magazine - 7.62x51mm

From Episode 2x04, "Deus Ex Machina"

Machine Guns

FN MAG (mocked up as M240B)

In Episode 1x04, "And the Ground, Sown with Salt", Michael (Jason Priestley) carried an FN MAG (mocked up to resemble a U.S. mil-spec M240B), introducing himself to Jeremiah and Kurdy by executing their informant with it.